NATURE: Crash: A Tale Of Two Species

Airs Sunday, May 23, 2010 at 4 p.m. on KPBSTV

Above: Each spring, the humble horseshoe crab (pictured), a creature that has remained virtually unchanged for 300 million years, produces millions of eggs that are the lifeline for a tiny bird called a red knot, which migrates 10,000 miles from South America to the Arctic each year.

At the center is the humble horseshoe crab, a creature that has remained virtually unchanged for 300 million years. Its annual spring spawning produces millions of eggs that are the lifeline for a tiny bird called a red knot, which migrates 10,000 miles from South America to the Arctic each year.

Scientific and medical communities have discovered that the crab also provides an indispensable testing agent for drugs and vaccines, as well as resources for human optics and burn treatment. But horseshoe crab numbers are plummeting from their new use as bait for the fishing industry, dropping by two-thirds since 1990. The precious pyramid depending on this age-old creature is about to come crashing down. Watch an excerpt from the film below, or watch the full episode online.

Video Excerpt: Nature: Crash: A Tale Of Two Species

Horseshoe crabs' blue blood, which contains copper, not iron, is prized by the biomedical community for its ability to detect bacteria in human medicines. It's just one of the amazing qualities of the 350-million-year-old evolutionary marvel detailed in "Crash: A Tale of Two Species."